Amine-phosphorus-containing adducts and motor fuel containing same



United States Patent 3,305,330 AMTNEPHQSPHURUSCONTAWTNG ADDUCTS ANDMOTOR FUEL CONTAINING SAME Frederic C. McCoy, Beacon, George W. Eclrert,Walppingers Falls, and Edwin C. Knowles, Poughkeepsle, N.Y., assignorsto Texaco Inc., New York, N.Y., a corporation of Delaware No Drawing.Filed Nov. 20, 1963, Ser. No. 325,180 14 Claims. (Cl. id-69) Thisinvention relates to novel amine-phosphorus-containing adducts and to ahydrocarbon fuel composition containing same having excellent surfaceignition properties. More particularly, the fuel i a leaded gasolinecontaining a combustion chamber deposit modifier which reduces surfaceignition and other harmful effects brought about by the formation andlaydown of deposits in the combustion chamber of a gasoline engine.

Most conventional gasolines contain an alkyl lead compound, such astetraethyl lead and tetrameth-yl lead, as an anti-knock compound toimprove the octane level of the gasoline. During combustion, the alkyllead compounds break do-wn to lead oxide and lead salts and formdeposits in the combustion chamber of the engine. These depositsinterfere with proper engine operation. Specifically, the lead depositswhich are characterized by a low ignition temperature becomeincandescent at engine operating temperatures. These glowing orincandescent deposits cause premature firing of the fuel-air mixtureduring the compression stroke of the combustion cycle resulting inuneven firing in the engine with concomitant loss of power and anaudible rumble noise. This phenomenon is known as surface ignition.Combustion chamber deposits also seriously reduce the efficiency of thesparkplugs even to the point of causing them to misfire completely. Thisis a serious or critical defect particularly in the case of leadedgasoline for aircraft operation.

The formation of lead deposits in gasoline engines has been greatlyreduced by employing scavenger agent in convention-a1 leaded gasolines.Scavenger agents are compounds capable of reacting with the tetraalkyllead compounds during combustion to produce volatile lead compounds. Theprincipal scavengers in use are alkylene dihalides, such as ethylenedichloride, ethylene dibromide and their mixtures. These compounds bringabout the formation of lead chloride and lead bromide which, be ingvolatile, are substantially removed from the engine during the exhaustcycle. Unfortunately, minor amounts of the lead compounds remaindeposited in the engine creating a surface ignition problem which isparticularly serious for modern high compression engines.

Considerable research has been conducted to reduce or overcome thesurface ignition problem caused by combustion chamber deposits. This hasled to the discovery of certain phosphate esters which are effective inreducing surface ignition. Indeed, certain amyl phosphate esters haveachieved some degree of commercial acceptance. The known phosphateesters, however, have harmful side effects on gasoline. The principalobjectionable feature of these phosphate esters is that they lower theoctane value of gasoline, a particularly serious drawback where onesobject is to produce the highest quality gasoline on a competitivebasis.

The present invention provides a novel class ofaminephosphorus-containing adducts and a leaded gasoline con- PatentedFeb. 21, 1967 ICC taining said adducts which exhibits an outstandingreduction in surface ignition. The amine-phosphorus-containing adductsare also useful for imparting anti-wear properties to minerallubricating oils.

An unexpected feature of the invention is that the adducts have noharmful or deleterious efiect on the overall octane quality of thegasoline. Another surprising feature is that the adducts are moreeffective for inhibiting surface ignition than the commerciallyavailable aryl phosphate esters.

The amine-phosphorus-containing adduct of the invention is representedby the formula:

in which R is an aliphatic radical having from 8 to 30 carbon atoms, Ris either hydrogen or an aliphatic radical having from 1 to 30 carbonatoms, X is a metal salt from the group consisting of zinc and aluminummonoand di-hydrogen phosphate and zinc and aluminum monoand di-hydrogenphosphite, y is an integer from 1 to 12 and the total number of carbonatoms in said adduct is at least 24. The motor fuel of the invention isa leaded gasoline containing a minor deposit-modifying amount of theabove described adduct. More particularly, the leaded gasoline willcontain from about 0.01 to 1 theories of the adduct, as described laterin more detail.

Amines which can be employed to prepare the adduct of the invention areamines having one or more aliphatic radicals in which at least onealiphatic radical has at least 8 carbon atoms. This requirement togetherwith the requirement of at least 24 carbon atom in the adduct iscritical to insure the solubility of the adduct in a leaded gasoline.The effective amines correspond to the formula:

wherein R is an aliphatic radical having from 8 to 30 carbon atoms and Ris hydrogen or an aliphatic radical having from 1 to 30 carbon atoms. Ris generally a branched chain alkyl radical because of the readyavailability of these materials. Prefer-ably, R is a tertiary alkylradical having from 12 to 30 carbon atoms.

Examples of specific effective amines include la'urylamine,2-ethylhexylamine, tri-n-octylamine, tridecylamine, tetradecylamine,hexadecylamine, octadecylamine, eicosylamine, tricosylamine,nonacosylamine, methyldodecylamine, dimethyldodecylamine,methyloctadecylamine, dimethyloctadecylamine. Particularly preferredamines are certain commercially available mixtures of tertiary alkylprimary amines. For example, a mixture of tertiary alkyl primary aminesin which the alkyl radical comprises a mixture of alkyl groups havingfrom 11 to 14 carbon atoms is available under the name Primene 8l-R.Another commercially available amine is the mixture of tertiary alkylprimary amines in which the alkyl radical comprises a mixture of alkylgroups having 18 to 24 carbon atom sold under the name Primene JM-T.

The adducts of the invention are prepared by mixing from 1 to 12 molesof an aliphatic amine with a mole of a zinc or aluminum salt of an acidphosphate or phosphite defined above. The reactants are generally heatedat a moderate temperature from about to C. to effect formation of theadduct. The reaction is usually accomplished by refluxing the reactantsin a solvent, such as benzene or toluene, the solvent being finallystripped off using conventional methods to recover the adduct.

Examples of adducts of the invention and the mole ratio of theircomponent parts, i.e., of the amine and metal salt are given below:

The amine-phosphorus-containing adduct of the invention is added to amotor fuel in the gasoline boiling range containing an anti-knock amountof a tetra-alkyl lead compound. The motor fuel may consist of anyhydrocarbon fuel including paraffinic, naphthenic, and aromatic hhydrocarbons or mixtures thereof suitable for use in aninternal-combustion, spark-ignition engine. These fuels are derived bythe distillation of crude oil, by the catalytic or thermal cracking ofgas oils, by the alkylation of isoparaffins with olefins, or by thepolymerization of olefins. The boiling point of the motor fuel orgasoline will generally be in the range from about 100 F. to about 450F. The motor fuel of the invention will contain a'tetra-alkyl leadcompound, such as tetraethyl lead, in a concentration from about 0.5 ml.to about ml. or more per gallon of fuel. The motor fuel may also containa number of additives conventionally employed in a gasoline, such asscavengers,

anti-oxidants, stabilizers, dyes, and metal suppressors.

The amount of the phosphorus-containing adduct employed in the gasolineof the invention is expressed in terms of theories. One theory of thephosphorus-containing adduct is defined as the amount of the adductwhich will provide sufiicient phosphorus to react .stoichiometricallywith the lead atoms in the tetra-alkyl lead anti-knock compound presentto form the compound Pb (PO The adduct is blended into the leadedgasoline in a concentration ranging from about 0.01 theory to about 1theory in accordance with the foregoing definition based on the leadcontent of the fuel. Concentrations between about 0.05 and 0.5 theoryare in the preferred range for the suppression of surface ignition.

Gasoline containing the adduct of the invention was tested foreffectiveness in a single cylinder CPR L-head engine with an 11.3/ 1compression ratio. The engine was continuously run on the test fuel overa 20-hour test period during which time engine operation was alternatedbetween a 50-second idle cycle (600 rpm.) and a ISO-second full throttlecycle (900 r.p.m.). The surface ignition count rate was obtained usingan ionization gap (sparkplug) as the surface ignition pickup coupled toa recording counter device. The surface ignition rate is expressed asthe number of counts per hour, the lower the count value the better thequality and performance of the fuel.

Tests were conducted using a high octane blended gasoline as the motorfuel. This gasoline containing 40 percent aromatic hydrocarbons boiledin the range of 97 to 373 F., had a research octane number of 101.9 andcontained 3 ml. of TEL per gallon. The adduct of the invention wasblended into the leaded gasoline to provide phosphorus in the amountsindicated as theories of phosphorus according to the foregoingdefinition.

Example .I

. When 0.3- theory of the foregoing adduct was employed,

the surface ignition count dropped to 185. At a concentration of 0.6theory, the surface ignition count was 65.

Example 11 Example III The adduct formed from Primene J M-T and zincmonohydrogen phosphite in a mole ratio of 2:1 respectively was blendedinto the base fuel having a surface ignition count level of 315. At aconcentration of 0.2 theory for the adduct the surface ignition countlevel dropped to 120. This adduct also gave a substantial improvement insurface ignition when employed in a concentration of 'O.l5 theories.

The adduct of Primene 81-R and zinc monohydrogen phosphite in molarratio of 2:1 respectively gave a substantial reduction in surfaceignition when employed in a concentration of 0.05 theory. 1 I

The adducts of the inventionhave given outstanding improvements in thesurface ignition of leaded gasoline.

This improvement was obtained without any loss or reduction in theoctane value of the fuels tested. In contrast to the foregoingimprovements, Primene JM-T and tricaprylylamine adducts of phosphoricacid in mole ratios of 3:1

respectively did not suppress the surface ignition of the base fuel.

Obviously, many modifications and variations of the invention'ashereinbefore set forth may be made without departing from the spirit andscopethereof, and therefore, only such limitationssh'ould be imposed asare indicated in the appended claims.

We claim: 1. An amine-phosphorus-containing adduct represented by theformula: v

in which R is an aliphatic hydrocarbon radical having from 8 to 30carbon atoms, R is selected from the group consisting of hydrogen and analiphatic hydrocarbon radical having from 1 to '30 carbon atoms, X is ametal salt selected from the group consisting of zinc and aluminummonoand di-hydrogen phosphate, y is an integer from 1 to 12 and thetotal number of carbon atoms in" said adduct is at least 24. t

2. An adduct according to claim 1 consisting of a primary amine and zincdi-hydrogen phosphate.

3. An adduct according to claim 1 consisting of a pri-' mary amine andaluminum di-hydrogen phosphate.

4. An adduct according to claim 1 consisting of a C tertiary alkylprimary amine and zinc di-hydrogen phosphate in a 4:1 mole ratiorespectively.

5. An adduct according to claim 1 consisting of a C1844 tertiary alkylprimary amine and aluminum di-hydrogen phosphate in a 12:1 mole ratiorespectively.

6. A motor fuel in the gasoline boiling range containing a minor amountof an organo-lead anti-detonant and from about 0.01 to 1.0 theory of anamine-phosphoruscontaining adduct represented by the formula:

cal having from 1 to 30 carbon atoms, X is a metal salt selected fromthe group consisting of zincand aluminum monoand di-hydrogen phosphateand zinc.and aluminum monoand 'di-hydrogen phosphite, y is an integerfrom 1 to 12 and the total number of carbon atoms in said adduct is atleast 24.

7. A motor fuel according to claim 6 in which said adduct consists of aprimary amine and zinc di-hydrogen phosphate.

8. A motor fuel according to claim 6 consisting of a primary amine andaluminum di-hydrogen phosphate.

9. A motor fuel according to claim 6 in which said adduct consists of aprimary amine and zinc mono-hydrogen phosphite.

10. A motor fuel according to claim 6 in which said adduct consists of aC1844 tertiary alkyl primary amine and zinc di-hydrogen phosphate in a4:1 mole ratio respectively.

11. A motor fuel according to claim 6 in which said adduct consists of aC1844 tertiary alkyl primary amine and aluminum di-hydrogen phosphate ina 12:1 mole ratio respectively.

12. A motor fuel according to claim 6 in which said adduct consists of aC1844 tertiary alkyl primary amine and zinc mono-hydrogen phosphite in a2:1 mole ratio respectively.

13. A motor fuel according to claim 6 containing 0.5 to 5 ml. of anorgano-lead anti-detonant.

14. A motor fuel according to claim 6 in which said organo-leadanti-detonant is tetraethyl lead.

References Cited by the Examiner UNITED STATES PATENTS 2,375,236 5/1945Miller 4468 X DANIEL E. WYMAN, Primary Examiner.

W. J. SHINE, Assistant Examiner.

6. A MOTOR FUEL IN THE GASOLINE BOILING RANGE CONTAINING A MINOR AMOUNTOF AN ORGANO-LEAD ANTI-DETONANT AND FROM ABOUT 0.01 TO 1.0 THEORY OF ANAMINE-PHOSPHORUSCONTAINING ADDUCT REPRESENTED BY THE FORMULA: